Milling machine



W. F. HUCK MILLING MACHINE Nov. 10, 1953 Filed Jan. 25

K R m R m M m Patented Nov. 10, 1953 UNITED STATES ATENT OFFICE MILLINGMACHINE Application January 25, 1949, Serial No. 72,631

7 Claims.

My present invention relates to milling machines, and more particularlyto milling machines that are used for machining the rear surfaces offlat printing plates.

In order to produce high grade printed matter it is important thatprinting plates be accurately formed. One of the operations performed onflat printing plates is to mill or machine the rear surface of theplates. This operation must be performed with a high degree of accuracyin order that the finished plate will be of exactly the correctthickness at all points across the plate, and so that the rear surfacewill be perfectly smooth. furthermore it is important that the millingmachine used be capable of accurate and swift adjustment and that it beconstructed in such a manner that the milling cutter can be readilyremoved and replaced.

Machines now in general use, for the above stated purpose, presentdecided disadvantages, inasmuch as in the past inaccuracies haveresulted from the inability of the machines to maintain the requiredaccuracy. Also it has been difficult and inconvenient to adjust suchmachines so that they would cut evenly across the plates from one end tothe other. Furthermore, it has been diiiicult to accurately install anew cutting unit. Therefore, in view of the disadvantages which attendthe use of the ordinary type of printing plate millin machine, mypresent invention has as one of its objects to provide an assemblage ofparts that will form an improved milling machine that is capable ofmilling the rear surface of a flat printing plate to a high degree ofaccuracy.

Another object of my invention is to provide an improved milling machinethat is capable of rapidly producing flat printing plates that areexactly the same thickness at every point across the plate.

A further object of my invention is to provide an improved millingmachine for printing plates that can be quickly set to mill a fiatprinting plate to any desired thickness.

A still further object of my invention is to provide a milling machinefor flat printing plates, in which the milling cutter can be quickly andeasily removed, and accurately replaced.

Other important objects of my invention will be apparent from thefollowing description and appended claims.

A complete understanding of my invention can be had by reference to theattached drawings and the following description. On the drawings:

Fig. 1 is a vertical cross sectional view taken through a printing platemilling machine embodying my present invention,

Fig. 2 is a horizontal sectional view as seen along the dash-dot line Z2of Fig. l, and

Fig. 3 is a fragmentary front elevational view of the machine shown inFig. 1.

In the drawings I have shown only those portions of aflat-printing-plate milling machine that are essential to theunderstanding of my invention, and it will be understood that the partsof a complete milling machine which I have not disclosed will beconstructed in accordance with the prior art teachings.

In the drawings, numeral lfi designates a supporting frame havingvertical side frames I I and H, the bottom pedestal of the frame notbeing shown. Frame Ii! supports a movable T-shaped bed I2 on a pair ofways I3I3' and between a pair of side guides I5I 5, both the ways andthe guides being formed as integral parts of the frame II].

The bed I2 supports a printing plate P which may be held to the bed I2by clamps (not shown) and which is prevented from longitudinal movementalong the bed I2 by a shoulder I2a formed on the left end (Fig. 3) ofthe bed I2. The ways I3I3 and guides I5I5' allow the bed I2 to be movedin a direction which is at right angles to the plane of the drawing inFig. l and to the right or left as indicated by the arrow I6 of Fig. 3.This movement of the bed I2 is obtained by a reversible force, forexample a reversible motor and suitable control, which forms no part ofmy present invention and therefore is not disclosed.

The right and left side frames II and II are provided with verticallydisposed cavities I'I--II'. The cavity ll is equipped with a pluralityof machine elements including a vertically disposed jack stem It; a wormgear [9; a worm ZI drivingly engaging the worm gear It; a portion of ahorizontally disposed shaft 22, one end of which is rotatably supportedfrom the-frame I I in a bearing 23 and which has keyed to it the worm2I; a stepped washer 2t; coiled spring 26; a bottom cover 21, which isscrew held to the bottom of the frame II; a vertically disposedadjusting screw 28 with lock nut 29; a side cover 3|. The left end(Figs. 1 and 2) of the shaft 22 carries an operating wheel 38, which isheld to the shaft 22 by the usual key, washer and screw. Jack stem Ithas a cylindrical guide portion 32 which is slidably mounted in acylindrical guide hole portion 33 of the cavity ll. Directly above eachguide 32 the stem I8 has an integrally formed rectangular flange head34. Below the guide 32 the stem I8 is externally threaded as at 36 andthereby carries the worm gear |9 which has appropriate internal threadsfor engaging the threads 36 on the stem l8. Directly below the threads36, the stem It has a reduced cylindrical portion 37, the upper part ofwhich carries the stepped washer 24, and the lower part of which isslidably carried in an internal cylindrical guide recess 38 formed inthe upper portion of the cover 23. The coiled spring 26 surroundsportions of the washer 24 and the cover 21 and provides a lift for thestem l8 by forcing the washer 24 against the bottom of the threadedportion 36.

The side frame H is provided with a downfacing thrust bearing surface39, and the spring 26 forces the upper side face 4| of the gear l9against the thrust surface 39. The spring 26 is strong enough tomaintain a firm contact at all times between the upper surface 4| of thegear l9 and the thrust surface 39.

The cavity [1, and the elements associated therewith is, except for afew features later to be described, identical with the cavity l1 and theelements associated therewith. For this reason the cavity H and theelements associated therewith will not be described in detail but thesame elements of both are designated by the same reference numeral, witha prime added, to the numeral associated with cavity I1.

The points wherein the elements of cavity 11' differ from those ofcavity I! are as follows: First, the two are of opposite hand; second,the cover 3| is provided with a bearing boss 42 which serves torotatably support the shaft 22 and also holds the worm 2| on the shaft,whereas the cover 31' is plain and the worm 2| is held to the shaft 22by a screw 43 and a washer 44; thirdly, the washer 24 and therefore thejack stem I8 is supported by one spring 26, whereas the washer 24 andstem |8' are supported by two concentric springs 26 and 26"; fourthly, apin 46 passes through a hole 41 in the frame I an may be made to enter ahole 48 provided in the worm 2|. By loosening the screw 43, the worm 2|,for adjustment purposes, may be rotated with respect to the shaft 22.This permits slight vertical adjustment of the jack stem l8 and therebypermits adjusting a cutter 49 presently to be described.

As best seen in Figs. 1 and 3, a bearing block 5| is held by bolts 52 tothe head 34 of the jack stem Hi. The block 5| has a flat bottom surfacethat rests on the top of the head 34 and also has a horizontallydisposed hole 53 bored therethrough. The hole 53 provides a space intowhich is inserted a cylindrical bearing cartridge 54, having at one endan inturned flange 56 and at the other end an outturned flange 51. Thecavity of the cartridge 54 supports the outer race ring of anantifriction ball bearing 58, and the front of the bearing cavity isclosed by a cover 59 having a small diameter collar 6| which enters thebearing cavity of the cartridge 54. The cover 59 is also provided with acentrally located axially extending hole 62, a radial flange 53, and anopen faced split ring 84. Bolts 66 hold the flange 63 to the flange 51,and bolts 61 hold the cover 59 and the bearing cartridge 54 to thebearing block 5|. An indicator gage 68 is attached to the cover 59 byscrews 69 and is protected from injury by the ring 64. The indicator 68is of conventional form and has a pointer 'H- which moves when the stem12 moves in. and out of the indicator. The lower end of the stem T2engages an upper end of a flat headed screw 13 which is threaded into alug I4 integral with the frame II, the screw 13 being held in apredetermined position by a lock nut 16. Thus the gage 68 indicates whenand by how much the bearing block 54 is raised or lowered. It will ofcourse be realized that the indicator could be mounted on the frame andthe stem 12 be arranged to engage a lug which moves as the cutter 49 ismoved.

The right (as seen in Fig. 1) jack stem l8 has a bearing block 5| boltedto it by bolts 52'. This block 5| is provided with a horizontallydisposed bore 53 which accommodates the outer race ring of a ballbearing 58, this ring being held in place by a cover H and bolts 18. Anoutwardly extending flange 19 of the block 5| is properly shaped tocarry a stator 8| of a motor, the stator being held in place by screws83. The two infacing portions of the bearing blocks 5| and 5| are joinedby a semi-cylindrical guard 84, which prevents accidental contact withthe cutter 49. The guard 84 also acts as a shield to guide flying chipsinto a suction hose 86 secured at one end to a hollow extension formedon the guard 84 and at the other end to suction collecting device, notshown.

A cutter supporting shaft 83 is supported on its left (Fig. 1) by theinner race ring of the ball bearing 58, and on its right by the innerrace ring of the ball bearing 58. The extreme right end of the shaft 88carries a rotor 89 for the motor stator 8|, the rotor being held to theshaft by a key 9|, a washer 92 and a bolt 93. A substantially centralportion of the shaft is formed into the shape of a frusto-conical collar94 having a key slot 86, and the portion of the shaft 88 to the left(Fig. l) of the collar 94 is reduced in cross section and is ofcylindrical form. The cutter 49, which may otherwise be of conventionalform, has special cone-shaped holes 91 and 91 at its two ends. Thecutter 49 is centered and carried on the shaft 88 by having the conicalend 91' engage the frusto-conical collar 94 and by having a conicallyshaped sleeve 98, with four slots 99 equally spaced around itscircumference, pressed into the cone-shaped hole 91 of the cutter 49.The sleeve 98 is forced, longitudinally of the shaft 88, by the innerrace ring of the ball bearing 58, which in turn is forced along theshaft by a washer |ll| and a screw "2, the latter being threaded intothe end of the shaft 88.

The operation of the milling machine described above is as follows.Energization of the electric motor 8|--89 causes the shaft 88 and thecutter 49 to rotate, and energization and proper control (not shown) ofa motor (not shown) causes the bed l2 to move from the left to the rightas seen in Fig. 3. Since the plate P is held to the bed l2, the cutter49 will mill the up-facing reverse side of the plate 1?, it beingunderstood that the obverse side of plate P rests on the bed I2. Thethickness to which the plate P is machined will be indicated by theindicator pointer H and can be regulated at will by the operator turingthe wheel 39. Turning the wheel 30 clockwise or counterclockwise causesworms 2| and 2| to rotate worm gears l9 and I9 respectively, whichaction causes the threads of the gears I9 and |9' acting with thethreads 36 and 36' of the jack stems l8 and I8 to raise or lower thejack stems as well as the bearing blocks 5| and 5|, and therefore toraise and lower the bearings 58--58, the shaft 88 and the cutter 49. Thepressure caused by the cutter 49 acting on the plate P causes a cutterpressure reaction on the bearings 53 and 58 which is to the right andupward as seen in Fig. 3. The upward component of this reaction is inthe same direction as the force produced by the heavy springs 26, 26'and 26". The strength of the springs are such that the forces producedby them are far in excess of the forces produced by the weight of thebearings 58 and 58, cutter 49, motor til-89, etc., and thus the springsprovide a firm preloading of the screw threads 36-35 in the worm gearsI9 and i9 and assure that the top face of the gears I9 and [9' arealways pressed firmly against the bottom of the thrust surfaces and 39respectively. From this it can be seen that the cutter reaction forcescannot and will not cause a lifting action. Furthermore, once a desiredsetting has been set, as shown by the indicator 68, the thickness of aplate P being cut will be constant before, during and after the cuttingoperation.

If it should become desirable to remove and replace the cutter this canbe done very rapidly by the following simple operation. First theindicator 68 is removed by removing the screws 69, and then the screws61 are removed thus detaching the bearing cartridge 54 and its cover 59from the block 5!. Removal of the indicator 68 uncovers the hole 62 inthe cover 59. Since the hole 62 is in direct line with the head of thescrew [62, the screw can be loosened by the use of a socket wrench (notshown) operating through the hole 68 and engaging a recessed socket inthe screw I62. As the screw I52 is loosened, its head engages the insideface of the cover 59 and since the cover 59 is held to the bearingcartridge 54 by screws 66, the loosening of the screw 61 causes thebearing cartridge 54, the bearing 58 and the cover 59 to move as a unitout of the hole 53 in the block 5|. This leaves the ball bearing 58within the cartridge 54' and thus protected from dirt or other injury.

With the hole 53 in the bearing block 5| open, the cone shaped sleeve 98is removed and the cutter 39 pulled through the hole 53, while the shaft88 remains in place being held by the right ball bearing 58.

From the above it is evident that I have provided a novel and greatlyimproved milling machine for milling printing plates. Among otherfeatures, it will be noted that I have provided a I backlash freeadjusting means for raising and lowering the milling cutter, which meanshas a direct reading indicator or guage, and which means insures that asetting once set will remain accurately adjusted regardless of thereactive pressure caused by the operation of the milling cutter. It willalso be noted that I have provided a mounting for the rotary millingcutter that will insure accurate centering on both ends and which at thesame time provides for easy removal and replacement of the cutter. Itwill be further noted that I have provided a means whereby both sides ofthe cutter can be adjusted to be accurately parallel.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. In a milling machine especially adapted for machining the reverseside of a flat printing plate, a frame, a pair of jack stems verticallymovable with respect to said frame, a milling cutter rotatably mountedon the upper end of said jack stems, a threaded portion on each of saidjack stems, a worm gear threaded on each of said threaded portions, aworm for driving each of said worm gears, a common shaft for 6simultaneously driving both of said worms, and a pin carried by saidframe and arranged to en gage one of said worms, whereby, said worm canbe held from turning while said other worm is adjustably turned.

2. A milling machine especially designed for machining the reverse sideof fiat printing plates, comprising a rotatable milling cutter, a pairof vertically disposed jack stems, a threaded portion on each of saidjack stems, a pair of antifriction bearings rotatably mounting saidcutter on the top of said jack stems, a worm gear carried by thethreaded portion of each of said jack stems, spring means for yieldinglysupporting said jack stems, a horizontally positioned thrust surfacepositioned adjacent each of said worm gears, and a pair of Worms forsimultaneously turning said worm gears.

3. A milling machine comprising a rotatable milling cutter, a pair ofvertically disposed jack stems, a pair of anti-friction bearingsrotatably mounting said cutter on said jack stems, a mem ber carried byeach of said jack stems, adjusting means for varying the relativeposition of each of said members with respect to its jack stem, springmeans for upwardly biasing each combination of said jack-stem and saidmember, limiting means for governing the upward movement of eachcombination of said jack stem and its member, and means forsimultaneousl varying the relative position of both of said members withrespect to their jack stems.

4. A milling machine comprising a rotatable milling cutter, a pair ofvertically disposed jack stems, a pair of anti-friction bearingsrotatably mounting said cutter on said jack stems, a member carried byeach of said jack stems, adjusting means for varying the relativeposition of each of said members with respect to its jack stem, springmeans for upwardly biasing each com-- bination of said jack stem andsaid member, limiting means for governing the upward movement of eachcombination of said jack stem and its member, and means forsimultaneously varying the relative position of both of said memberswith respect to their jack stems, and means for stopping thesimultaneous varying of the relative position of one of said memberswhile the other said member is adjustably varied.

5. A milling machine especially adapted for machining fiat printingplates comprising a rotatable milling cutter; a pair of side frames eachhaving a vertically disposed cavity, and each cavity having a guide holeportion, and a down facing thrust bearing surface; a vertically disposedjack stem in each of said cavities, and each jack stem having a guideportion located in said guide hole, an externally threaded portionlocated adjacent to said bearing surface, and a reduced cylindricalportion; a pair of antifriction bearings rotatably mounting said cutteron said jack stems; a worm gear carried by said threaded portion of eachof said jack stems, and each worm gear having an upper side faceengaging one of said thrust bearing surfaces; adjusting means forturning said worm gears with respect to said threaded portions; a washercarried on each of said reduced cylindrical portions below said threadedportions; a compression spring engaging the lower side of each of saidwashers; and a member engaging the lower end of each of said compressionspring and thereby causing said springs to yieldingly support said jackstems.

6. A milling machine especially adapted for machining fiat printingplates comprising a rotatable milling cutter; a pair of side frames eachhaving a vertically disposed cavity, and each cavity having a guide holeportion, and a down facing thrust bearing surface; a vertically disposedjack stem in each of said cavities, and each jack stem having a guideportion slidably fitted into said guide hole, an externally threadedportion located adjacent to said bearing surface, and a reducedcylindrical portion; a pair of ball bearings rotatably mounting saidcutter on said jack stems; a worm gear screwed to said threaded portionof each of said jack stems, and each worm gear having an up facingthrust surface engaging one of said thrust bearing surfaces; adjustingmeans for simultaneously turning said worm gears with respect to saidthreaded portions, a washer carried on each of said reduced cylindricalportions below said threaded portion; a compression spring engaging thelower side of each of said washers; and a member engaging the lower endof each of said compression springs and thereby causing said springs toyieldingly support said jack stems.

7. A machine especially adapted for machining flat printing platescomprising a rotatable milling cutter; a pair of upstanding side frameseach having a vertically disposed cavity, and each cavity having a guidehole in its upper portion,

and a down facing thrust bearing surface below said guide hole; avertically disposed jack stem in each of said cavities, and each jackstem having a guide portion positioned in said guide hole,

an externally threaded portion below said guide portion and positionedadjacent to said bearing surface, and a reduced cylindrical portionbelow said threaded portion; a pair of antifriction bearings rotatablymounting said cutter on the upper ends of said jack stems; a worm gearcarried by said threaded portion of each of said jack stems, and eachworm gear having an upper side face engaging one of said thrust bearingsurfaces; adjusting means engaging said worm gear and turning them onsaid threaded portions, a washer carried on each of said reducedcylindrical portions and being restrained from longitudinal movement onsaid stems; a compression spring engaging the under portion of each ofsaid washers and forcing each of the washers and stems upwardly; and. abottom cover supporting the other end of said compression spring.

WILLIAM F. I-IUCK.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 619,501 Potter Feb. 14-, 1899 1,479,073 Howard Jan. 1, 19241,602,860 Sleeper Oct. 12, 1926 1,623,346 Johnson Apr. 5, 1927 1,825,721Forward et a1 Oct. 6, 1931 1,942,592 Claybourn Jan. 9, 1934 2,171,519Belden et a1. Sept. 5, 1939 2,239,259 Turrettini Apr. 22, 1941 2,239,567Nenninger Apr. 22, 1941

